With the development of modern materials, such as readily molded plastics, there have been available on the market for many years flush valve assemblies for the tanks of water closets which include a number of parts molded from plastics thereby achieving economies of manufacture as well as the ability to fabricate complex shapes without requiring the mechanical interfitment of a plurality of individual discrete parts with entailed labor costs and potential for slight misassembly and resulting leakage from the tank.
Such valve assemblies commonly used in flush closets usually include a valve seat assembly for mechanical securement to the out flow aperture at the bottom of the tank, and a valve assembly mounted thereon for pivotal motion between valve closed position and thence through an acurate path to a valve open position, with the valve assembly pivoted to elevate the valve to its uppermost position in response to actuation of a flush lever or other conventional means.
Such devices are well known in the art and a great number of the same, as noted, have received wide commercial and public acceptance, and indeed are manufactured and installed in the many thousands of units.
Illustrative teachings of such devices and which also are found in the marketplace include the Flush Valve shown in U.S. Pat. No. 2,773,268 to Hurko et al or the Flush Toilet Accessory shown in U.S. Pat. No. 4,134,165 to Phripp et al, or other patents as U.S. Pat. No. 3,988,785, to Schoepe et al for example.
Accordingly, while the utilization of modern plastic materials has facilitated the ready fabrication and availability of complete valve assemblies at overall low cost, a disadvantage associated with such constructions is that fracture of any one small area thereof may require replacement of the entire assembly, rather than just repair of a small portion thereof or its simple and effective replacement.
Specifically, in connection with pivoted lifting flush valves of this type, it is normal practice to provide stop means to limit the upward swinging and opening movement of the valve. Such stop means are readily provided by the engaging abutment of a stop extension on the valve arm with a stop surface as an intercepting wall on the fixed support for the pivoted valve arm. As in the course of use, the valve is opened a great number of times in ordinary flushing operations, the valve arm stop extension makes repeated contact and impact against its stop surface on the arm support.
This has not infrequently led to fracture of the stop surface on the support, whereupon the actuation of the valve at that time, or on its succeeding actuation, will cause the same to swing through its pivot path to an excessive degree and to an overcenter position, whereby the valve will not readily close in ordinary manner, or indeed, is unable to close at all.
Upon such occurrence, the householder has the immediate problem of attending to the continuous and unintended water flow through the tank as well as the necessity of obtaining attention to the mechanical valve problem.
As indicated, the result of the fracture of even a small area in the complexly molded plastic unit normally requires replacement of the entire valve assembly or a major portion thereof at substantial cost and inconvenience to the householder or to the owner and operator of facilities having plural or a multiplicity of flush closets, as apartments, office buildings, etc. Further, it will be evident that the cost and waste of water alone renders such valve inoperable absolutely intolerable. Illustratively, in a single home toilet, for example, the water loss in just one day's time would be on the order of 7,200 gallons.